Mark the centerline on the neck block – If your blocks are pre-cut, a piece of tape can be used to cover the gap at the truss rod slot.The block is our Martin compatible true "bolt on"

Get the block centered and flush with top of the rim. Hold it in place with a couple of clamps.

Drill two #54 holes through the rim sides into the neck block. Use care to locate the holes so they will be under the neck heel and clear of the mortise or dovetail cut out. Pin in place with #18 brads.

Remove the sides from the mold, apply glue, re-pin, apply the clamps --- make sure the rim joint is closed and the block is flush at the top. Notice that the block is proud of the rim on the back rim edge. It will be trimmed and contoured to match the back.

Place the rim back in the mold back edge down. Measure the height at the tail block

Adjust the height of the neck block so it is equal to the tail block. Insert shims under the rim to keep the top edge of the rim parallel to the mold base. Pinch the rim to the sides of the mold with the built-in clamps

Using a sanding stick (I use 80 grit glued to MDF) lightly sand the top edge of the rim. Even now it should be uniform all the way around including the tops of the blocks.

When assembling the kerfing I apply glue to the rim as well as the kerfing with a brush. My preference is the modern rounded reverse style kerfing. It provide a laminate effect which makes the rim much stiffer. I have found that the rim keeps its shape. This is important since the centerlines of the two blocks remain in the proper relationship with each other and perpendicular to the top edge. I also found that spraying a little water on the kerfing improves flexibility and helps prevent cracking. (If they do crack it is not a problem).

The 39 cent clamps from Home Depot work well if a little extra pressure is needed. Be careful they will dent the kerfing if the metal part hits the wood. I mostly use “high tech” spring clothespins. These are clothespins with a #32 rubber band wrapped around the jaws. Use plenty of clamps. It’s a good idea to have an inspection mirror in order to look at the bottom edge of the kerfing to make sure it is tight against the side.

Sand the top edge so everything is uniform

Applying kerfing for the back is the same except it needs to be just a tad proud so when it is contour sanded the inside edge is higher that the outside edge to match the back.

We use 1/8” x ¼” vertical grain Spruce for the side reinforcements. The spacing is 3” (note the 3x5 card no doubt this is the lazy man’s way.) Start at the tail block use the top kerfing to keep the marks perpendicular. Number the locations as you go.

Transfer the length to the reinforcement material, then cut with a razor saw. Mark the location on each piece so you know where to glue it.

As each reinforcement is cut to size, clean up the edges and chamfer all four visible corners. A block with 220 grit sand paper works well.

The large (generic) spring clamps from Home Depot are very strong and work good for this application. If you do not have two dozen clamps, just work in batches of 2 or 4 --- the clamps can be removed and used for the next set in about thirty minutes. (some times we guitar builders get carried away with our drying time)

Because the tail block grain runs parallel to the side grain (this makes contouring the rim easier) we need to laminate a piece of 1/8” x 1” quarter sawn spruce to the tail block to eliminate the possibility of splitting.